308 loading problem

[Jgault]

I haven’t run into this before. I’m using a Hornady die. With Speer 168 match the picture below is the result. The jacket is being shaved until it becomes a bulge, then the brass crushes. Even when this didn’t happen there was still a slight shaving sometimes leaving a copper ring that easily pull off. I believe my case prep is correct, the brass is trimmed, chamfered and debuted. The die isn’t set to crimp, and the expander measures correctly at .306. I’m also having issues with Speer 165 soft points, while it doesn’t cause the issue with the shaving, it is tight resulting in a ring at the top of the bullet, sometimes rather deep. Hornady 150 SP worked better but still more force needed than I’m happy with. The brass is mixed including federal, ssa, Winchester and a few others. Any help would be appreciated.

 

[Jgault]

Pic

 

[918v]

Describe your case prep. From decapping to cleaning to lube, sizing, case neck treatment, etc.

Looks like too much friction in the neck.

 

[Jgault]

I run the cases through a wet tumbler and dry, then I use unique case line lightly, decap and size, trim using a Lyman trimmer, then the electric chamfer inside debur outside, wash again, dry load. I load allot of calibers without issue other than 308, and this is a semi recent die. I tried running a case through the expander several times and trying to seat, while better it was still tight.

 

[supercorndogs]

Measure the bullets. I know my dad had bunch once that were oversized at the base. If you pushed them through the neck they fell into the case.

 

[45-90]

If you wet tumbled them too long, that throws a burr in your champhered case mouth closing down the diameter from banging the case mouths against other cases and ss pins.
Rechampher them and see.

 

[straightshooter1]

PicView attachment 8432526

How many firings on the cases?

Obviously, the case neck is too tight. I'd be trying to find out why by measuring case neck OD before seating and the neck thickness to see if I'm getting the right neck tension. And if you're not annealing, the necks may be hardening where there's a lot of springback, making the necks tighter after each firing. . .???

 

[diggler1833]

If you are running a mandrel or bushing to get a known interference value (not just over an expander ball)...I'd start checking the diameter of the bullets.

I could certainly be wrong, but I'm leaning towards oversize bullets right now.

 

[918v]

I run the cases through a wet tumbler and dry, then I use unique case line lightly, decap and size, trim using a Lyman trimmer, then the electric chamfer inside debur outside, wash again, dry load. I load allot of calibers without issue other than 308, and this is a semi recent die. I tried running a case through the expander several times and trying to seat, while better it was still tight.

Your neck is too clean and too tight which causes galling and increased seating effort. Get some imperial graphite dry lube and lube the neck prior to seating bullets. The graphite won’t affect the powder but bullet seating will be nice and smooth.

 

[Jgault]

Your neck is too clean and too tight which causes galling and increased seating effort. Get some imperial graphite dry lube and lube the neck prior to seating bullets. The graphite won’t affect the powder but bullet seating will be nice and smooth.

Will do, is there as my difference between imperial and other graphite powder? Thank all of you by the way.

 

[918v]

I dunno. I always used imperial, mostly because it comes as a package with ceramic application media.

If you go that route dump out half the media from the jar because it comes full and is hard to shake. You have to be able to shake the jar so the graphite coats the ceramic balls. Then dunk the neck into the media a bunch of times so you get good coverage inside the neck.

Also, I personally use a .307” mandrel to expand the neck, that way I get .002” neck tension after springback. With a .306” expander you end up with .003” neck tension which gets progressively problematic as the neck hardens through multiple reload cycles.